A standard retractile motor-vehicle trailer hitch as described in German patent document 198 59 961 of F. Domke et al has a solid shaft bolted to the motor-vehicle frame and on which the inner end of an arm is pivoted. This arm has an outer end equipped with a standard hitch ball. The inner arm end can move angularly on the shaft between a use position with the hitch ball projecting up rearward of the rear bumper of the vehicle and a retracted position hidden behind the vehicle bumper.
In addition the arm inner end can move axially limitedly on the shaft between a locked position and an unlocked position. In the locked position interengaging formations on the frame and on the arm inner end fit together and prevent angular movement of the arm. This locked position can be assumed in both the use and retracted positions of the arm. In the unlocked position the formations are out of engagement with each other so that the arm can pivot freely between its end positions.
The coupling formations are axially interengageable teeth on the frame and on the arm inner end. The arm is moved along the shaft by an actuator fitted externally to an ed of the shaft. Thus the user grips a knob end of this actuator, operates it to unlock the arm, and then pivots the entire arm to move it between its end positions.
Such operation is fairly difficult and cumbersome. The user must typically crouch behind the vehicle and grope under the frame to operate the hitch. Furthermore the hitch is exposed to road dirt so that it is normally filthy, something that not only makes handling it difficult, but that also leads to corrosion and deterioration of the actuating elements.